The images you've posted are reduced in size and have their EXIF info stripped so its hard to state specifically. For my eye, the outdoor images, I'm assuming, are as the indoor where you had auto ISO setting and possibly auto White Balance.

For my tastes, I would set ISO80 and WB to cloudy. Usually I'd leave the setting on P-Mode and use the histogram to see if I have any areas of under/over exposure. The histogram is your light meter and the grouping of the peaks indicate where the exposures are coming in at. If they're all pushed to the far right, you're tending to over exposure and get light, washed out details. Conversely, peaks crowded toleft side indicate under-exposure.

The understanding and use of the histogram alone will go a long way to improving your image quality and exposures. Use the highlight mode, as well. Immediately after taking an image, the review mode will show areas of over exposure by blinking. If this is the case, adjust the shutter/aperature and/or change the area you're metering on to compensate. A silight under-exposed image will allow for more details to be available using post processing software, even if its the free Picasa2 software.

I'd start with practice and experience with taking images using the histogram feedback and deliberately try under/over exposing images so you get a feel on how to read and adjust. Once you feel comfortable using it, you should see a noticeable improvement in the color/dynamic range and contrasts in your outdoor images. (I'd leave the indoor and flash/low light circumstances until you're more experienced with outdoors and good lighting.)

One final suggestion, for portrait/group photos outdoors in harsh lighting and if everyone is wearing caps or their face is shaded, try using the flash as a fill-in light.

After a few episodes of practice with using the histogram and working on improving the image exposure/contrasts, post a few representative images with the EXIF info so others can interpret and offer comments/guidance/suggestions. remember, your digi came with free film called the delete button...:-)

By the by, you may also want to read some of the info on basic photography hints at